1. Field of the Invention
The present invention relates to planar optical displays, and, more particularly, to an ultrathin display panel and a method of making an ultrathin display panel.
2. Description of the Background
Optical screens typically use cathode ray tubes (CRTs) for projecting images onto the screen. The standard screen has a width to height ratio of 4:3 with 525 vertical lines of resolution. An electron beam is scanned both horizontally and vertically across the screen to form a number of pixels which collectively form the image.
Conventional cathode ray tubes have a practical limit in size, and are relatively deep to accommodate the required electron gun. Larger screens are available which typically include various forms of image projection. However, such screens have various viewing shortcomings including limited viewing angle, resolution, brightness, and contrast, and such screens are typically relatively cumbersome in weight and shape. Furthermore, it is desirable for screens of any size to appear black in order to improve viewing contrast. However, it is impossible for direct view CRTs to actually be black because they utilize phosphors to form images, and those phosphors are non-black.
Optical panels may be made by stacking waveguides defining a wedge and having a narrow inlet face along the bottom of the wedge and a vertical outlet screen disposed obliquely to the inlet face. Such a panel may be thin in its depth compared to its height and width, and the cladding of the waveguides may be made black to increase the black surface area, but such a panel may require expensive and cumbersome projection equipment to distribute the image light across the narrow inlet face, which equipment thereby increases the total size of the panel.
Therefore, the need exists for an optical panel which possesses the advantages corresponding to a stacked waveguide panel, but which does not require the use of expensive and cumbersome projection equipment, nor suffer from the increase in size necessitated by such equipment.
The present invention is directed to an ultrathin optical panel. The panel includes a plurality of stacked optical waveguides, wherein the plurality forms an outlet face and an inlet face, and at least one coupler connected to the inlet face which redirects light along a non-perpendicular axis to the inlet face to a perpendicular axis to the inlet face. The coupler allows the panel to be created using simple light generating equipment, and allows that equipment to be mounted in close proximity with the inlet face.
The present invention is also directed to a method of producing an ultrathin optical panel. The method includes vertically stacking a plurality of glass sheets, which sheets may be coated with a transparent cladding substance or may be uncoated, fastening together the plurality of stacked coated glass sheets using an epoxy or ultraviolet adhesive, applying uniform pressure to the stack, curing the stack, sawing the stack to form an inlet face on a side of the stack and an outlet face on an opposed side of the stack, bonding a coupler to the inlet face of the stack, and fastening the stack, having the coupler bonded thereto, within a rectangular housing having an open front which is aligned with the outlet face, the rectangular housing having therein a light generator which is optically aligned with the coupler.
The present invention solves problems experienced in the prior art, such as the required use of expensive and cumbersome projection equipment, by providing a light inlet which, though smaller in surface area than the outlet face, is large enough and symmetrical enough to not necessitate the use of expensive projection equipment. The present invention also retains the advantages which correspond to a stacked waveguide panel, such as improved contrast and minimized depth.
Those and other advantages and benefits of the present invention will become apparent from the detailed description of the invention hereinbelow.